I just took the test, the correct answer is "to reinforce his main argument that slavery opposes the ideals of America.".
Yes because that makes sense
Answer:
Average is the middle, or the "normal".
In the case of this question the average family would be a middle class family.
Using a natural voice is important than using an ideal voice. The passage tells us that many people that have the prestige of having a low voice, try to alter their voice, which can cause voice damage. While Choice C is correct, it is not the main idea, while Choice A would be.